Physio Ch 7 Nervous System 12th ed

Muscarinic ACh receptors act through ____________ activation of K+ channels.

G-protein

Benzodiazepines act by increasing ________ activity.

GABA

Spatial summation

occurs because of the convergence of many neurons on a single postsynaptic cell

The mechanism that allows many Na+ ions to move into the axon is

positive feedback.

The membrane of resting nerve cells is more permeable to ____________ ions than ____________ ions.

potassium, sodium

If the binding of muscarine to its receptor in the heart causes the beta-gamma complex of the G-protein to bind to a K+ channel,

the K+ channel will open, leading to hyperpolarization and inhibition

In a myelinated axon, Na+ channels are

concentrated at the nodes of Ranvier.

Ion channels that open in response to depolarization are called

voltage-gated channels.

Fetal neuron growth requires the actions of a group of chemicals known as

neurotrophins.

Addictive drugs, as well as nicotine, activate dopamine release in the

nucleus accumbens

The average resting membrane potential of an axon is

-70mV.

Postsynaptic inhibition is caused by

GABA and glycine

The most common neurotransmitter in the brain is

GABA.

Both long-term potentiation and long-term depression requires release of ___ from the postsynaptic neuron membrane

Ca2+

Acetylcholine can induce hyperpolarization by

binding to muscarinic receptors

Local anesthetics block conduction of action potentials in sensory neurons by

binding to sodium channels.

Synaptic plasticity involves structural changes in neurons such as

formation of dendritic spines

Degeneration of spinal motor neurons in adults may be due to a lack of ____________ factor.

glial-derived neurotrophic (GDNF)

Mutation of the N-methyl-D-aspartate (NMDA) receptor would affect the ability of ____________ to regulate neural function

glutamate

Excitatory postsynaptic potentials are produced by

glutamic acid

Chemical synapses

have a delayed impulse transmission.

Which of the following is NOT classified as a catecholamine?

histamine

Where is glycine released?

in the CNS

What causes presynaptic inhibition?

inactivation of Ca2+ channels, a second neuron causes a reduction in neurotransmitter release from another neuron, axoaxonic synapses

What coding system do neurons use to get a greater response?

increased frequency of stimuli

Catecholamines activate postsynaptic cells by

increased production of cyclic AMP

Inhibition of neuropeptide Y synthesis would

inhibit eating

At what region of the neuron are action potentials first produced?

initial segment of an axon

Which of the following is NOT true of axonal transport?

is a passive process

What process occurs when glutamate-releasing presynaptic neurons stimulate postsynaptic release of endocannabinoids that acts as retrograde neurotransmitters?

long-term depression

Enhancing the excitability of a synapse so that transmission is favored along certain

long-term potentiation

The mesolimbic dopamine neurons arise in the midbrain and terminate in the

nucleus accumbens

Temporal summation

occurs when a single neuron releases neurotransmitter rapidly

The myelin sheaths of CNS neurons are produced by

oligodendrocytes.

What action produces an IPSP on the postsynaptic membrane?

opening of Cl- channels into the neuron

Which of the following is true of axons?

originates at the axon hillock on the cell body

Which ion's movements is responsible for repolarization?

outward diffusion of K+

What type of autonomic fibers release ACh at effectors?

parasympathetic

Which of the following is NOT a function of astrocytes?

phagocytose foreign material in the CNS

The ability of a neuron to transmit charge through its cytoplasm is called cable properties and is very

poor.

An axon will depolarize only if the membrane potential reaches between -70mV and -55mV. This follows the

All-or-none law.

Which of the following is NOT true of long-term potentiation (LTP)?

Associated with the removal of AMPA glutamate receptors

______ synapses occur between axons of presynaptic cells and dendrites of postynaptic cells.

Axodendritic

The binding of a neurotransmitter to its receptor protein causes ion channels to open in the post-synaptic membrane. What type of gates are these?

Chemically-regulated gates and ligand-regulated gates are correct.

Which of the following is NOT an action needed for glutamate to open ion channels?

Cl- must pass through the open channel

Hyperpolarization in the postsynaptic cell is caused by

Inhibitory postsynaptic potentials and movement of K+ out of the cell are correct.

What type of neuron is found entirely in the CNS?

Interneuron and association neuron are correct

Blocking ____________ channels would prevent neuron depolarization.

Na+

What is NOT true of the relative refractory period?

Na+ channels are inactivated

During an action potential

Na+ influx causes depolarization.

What process is needed to return a membrane to its resting membrane potential with all ions in the correct locations?

Na+/K+ pump

____________ is an acetylcholinesterase antagonist used to treat myasthenia gravis

Neostigmine

Which of the following is NOT true of nicotinic-gated channels?

Only action potentials are generated.

The period of time when Na+ channels are recovering from their inactive state and K+ channels are still open is the

Repolarization and relative refractory period are correct.

Synaptic vesicles are docked to the plasma membrane of the axon terminal by a protein complex called

SNARE.

Action potential transmission in the PNS is decreased if which cells are damaged?

Schwann cells

The myelin sheaths of PNS neurons are produced by

Schwann cells.

What do muscarine and nicotine have in common?

They are both agonists for their respective receptors.

What medication acts by increasing the action of nitric oxide as a treatment for erectile dysfunction?

Viagra

Action potentials would be conducted most rapidly by

a 40 mm diameter myelinated axon.

Botulism toxin prevents release of ACh, causing

flaccid paralysis.

Cholinergic fibers use ____ as the neurotransmitter

acetylcholine

Which of the following is NOT true of histamine?

acts as a neurotransmitter in the brain to cause drowsiness

What is the action of the binding of muscarine to its receptors in the digestive system?

alpha subunits bind to K+ channels, close them, leading to depolarization

Sensory neurons

are pseudounipolar and carry impulses toward the CNS

The blood-brain barrier results mostly from the action of __________, a type of glial cell.

astrocytes

Which cells are needed for the formation of synapses in the CNS?

astrocytes

The most numerous of all cells of CNS nervous tissue are the

astrocytes.

Which division of the nervous system innervates involuntary effectors?

autonomic nervous system

Neurotransmitter release would be inhibited by

blocking Ca2+ influx in the axon terminal.

ATP and adenosine can act as neurtransmitters

by being released from astrocytes, as cotransmitters, as paracrine regulators.

Acetylcholine

can bind to nicotinic receptors.

Gliotransmitters

can stimulate neurons.

Which of the following is NOT true of norepinephrine?

causes depression in the CNS

What type of proteins are present at chemical synapses to ensure the close proximity of the presynaptic and postsynaptic membranes?

cell adhesion molecules (CAMs)

The brain and spinal cord comprise the

central nervous system.

What type of proteins are present in gap junctions that form water-filled channels between neurons?

connexins

Which of the following effect(s) acetylcholine synaptic transmission?

curare and botulinum toxin.

What type of neural pathway involves one neuron forming synapses with several postsynaptic neurons?

divergent

Neuroleptics, which are used to treat schizophrenia, are

dopamine antagonists

The brain produces lipid neurotransmitters called

endocannabinoids

Which of the following are natural analgesics?

endorphins, enkephalins, dynorphins

Which type of cell lines the ventricles of the brain and help produce cerebrospinal fluid?

ependymal cells

Excitotoxicity is caused by

excessive synaptic release of glutamate

Endogenous cannabinoids have effects similar to the active ingredient in

marijuana

The __________ dopamine system may be involved in emotional reward and drug addiction

mesolimbic

Which type of cell of the CNS is phagocytotic?

microglia

Which of the following is NOT a structural classification of neurons?

motor neuron

Retrograde transport

moves toward the cell body, moves membranes, vesicles, and viruses, uses molecular motor proteins of dynein.

The disease ______________ is characterized by destruction of CNS myelin sheaths and the formation of hardened scars.

multiple sclerosis.

Which of the following is NOT a functional classification of neurons?

multipolar

Which of the following is NOT a type of glutamate receptor?

muscarinic receptor

Regeneration of CNS axons may be prevented in part by inhibitory proteins in the membranes of the

myelin sheath.

Axonal regeneration is inhibited by

myelin-associated inhibitory protein.

White matter is

myelinated axons in the CNS.

The normal effect of -endorphin can be blocked by

naloxone

Repolarization is accomplished through a

negative feedback loop.

What structure is found around PNS axons that is NOT found around CNS axons?

neurilemma

The most abundant neuropeptide in the brain is

neuropeptide Y

Chemicals that stimulate action potentials in postsynaptic cells are called

neurotransmitters.

Curare is a competitive ACh antagonist at _____________ ACh receptors

nicotinic

Acetylcholine usually induces an excitatory postsynaptic potential when binding to ________ receptors and an inhibitory postsynaptic potential when binding to some ____________ receptors.

nicotinic, muscarinic

Relaxation of cerebral blood vessels would be stimulated by excessive ________ activity.

nitric oxide

Which gas(es) can function as a neurotransmitter?

nitric oxide and carbon monoxide

The gap of exposed axon in the myelin sheath is the

node of Ranvier.

What type of receptors will bind ATP and adenosine?

purinergic receptors

As the intensity of a stimulus increases, more axons will become activated. This process is called

recruitment.

Which of the following is NOT a function of neurotrophins?

regeneration of injured motor neurons

Endocannabinoids are retrograde neurotransmitters, meaning they are

released from postsynaptic neurons and diffuse to the presynaptic neuron

Conduction of an action potential in a myelinated axon is called

saltatory conduction.

Cells supporting neuron cell bodies in ganglia are termed

satellite cells.

What neurotransmitter is used by neurons with cell bodies in the raphe nuclei along the midline of the brainstem?

serotonin

Muscarinic ACh receptors are found in all of the following locations EXCEPT

skeletal muscle

Nitric oxide

stimulates the dilation of blood vessels

What is the predominant affect of stimulation of nicotinic-gated channels?

stimulation due to influx of Na+ ions

Which poison inhibits glycine receptors?

strychnine

The capacity of synapses for alteration at the molecular level is termed as

synaptic plasticity

The varied strength of synaptic transmission is called

synaptic plasticity

What is NOT true of conduction through dendrites and cell bodies of neurons?

they are action potentials

Which of the following is NOT true of EPSPs?

they have a refractory period

The minimum depolarization needed to open Na+ gates is called the

threshold.

A bundle of axons in the CNS is called a/an

tract

Which of the following is NOT true of dendrites?

transmits action potentials toward the cell body

Serotonin is synthesized from the amino acid

tryptophan

MAO inhibitors may cause hypertensive crisis by a person eating foods rich in

tyramine

What amino acid are dopamine, norepinephrine, and epinephrine derived from?

tyrosine

Neurotransmitters

usually regulate ion channels.

What is present at the axon hillock that allows the production of action potentials?

voltage-gated channels